Summer Solstice Rare Celestial Treat

strawberry-moon662x0_q70
The 2009 “Strawberry Moon”, 27 June, 2009. Click image for the expanded view.

This year’s Summer Solstice occurs this Monday, 20th June at 22:34 UTC (6:34 PM, EDT). On the occasion of the Summer Solstice, the sun crosses the meridian at its highest southern elevation (Northern Hemisphere) at local noon resulting in this being the longest day of the year. This year, however, we’re in for a special treat. Rising as the sun sets, the sun having just passed the moment of the Summer Solstice, is this year’s “Strawberry Moon”. The June full moon is named for it’s significance as a signal to the the Algonquin tribes to begin their harvest of the ripened fruit. Although neither occasion is of no real significance, that there is such a confluence on the same date is quite rare and is something that occurs, quite literally, once in a lifetime with the last such occurrence 70 years ago. A calendar of full moon dates, their names, significance and meaning can be found in the “Old Farmers Almanac” and in Fred Espenak’s Ephemeris.

Screenshot 2016-06-18 17.01.22
The location of the sun relative to the stars on the date of this year’s Summer Solstice, 6 hours before the actual event. Note the proximity of Venus to the sun and the location of Mercury. Note, also, the sun’s “Declination” (celestial latitude) of +23.5, indicating that it is 23.5 degrees above the Celestial Equator (celestial latitude of 0, corresponding to the latitude of the Earth’s equator of zero). Click image for the expanded view.
Screenshot 2016-06-18 17.12.38
The placement of the sun in the sky on 20 June at the moment of the Summer Solstice, its greatest separation from the Celestial Equator, 22:34 UTC. Click image for the expanded view.

Caused by the Earth’s axial tilt, the change of climate as the seasons transition, from one into the next, can be understood with a simple exercise using a flashlight and a globe. With the globe’s axis leaning towards you, position the flashlight above the Tropic of Cancer (Summer, +23.5 North Latitude) and note that the light’s (sun’s) projection on the globe is round and concentrated; if the light is tilted north or south of this point, note how the light becomes elongated and more spread out. Repeat the same exercise with the globe’s axis leaning away from you, positioning the sun above the Tropic of Capricorn (Winter, -23.5 South Latitude) and note how the beam becomes more spread out and elongated when pointed north or south as in the previous exercise. On the summer solstice in the Northern Hemisphere (June), the sun is at the zenith at the Tropic of Cancer and at the zenith at the Tropic of Capricorn on the Summer Solstice in the Southern Hemisphere (December). As the sun’s light becomes more spread out and elongated, the climate changes and the prevailing temperature drops. At 23.5 degrees north and south of the equator, the Tropics of Cancer and Capricorn represent the deviation of the ecliptic (the sun’s apparent path across the sky) from the Celestial Equator, the projection of the Earth’s equator on the sky.


FullMoonAntares07312009_final
Wide field view of the July 2009 full moon following the lunar occultation of the red supergiant star Antares, to the left (east) of the moon’s western limb. South is up, west is to the right. Click for expanded view.
FullMoonAntares07312009Large_final
Larger scale image of the July 2009 full moon just following the lunar occultation of the red supergiant star Antares.  The star can be seen to the left (east) of the moon’s western limb. Click image for expanded view.

Above, the July, 2009 full moon as imaged by the author, one month after the June 2009 Strawberry moon, pictured above and presented as this article’s featured image. The July 2009 full moon was of particular significance as it occulted (passed in front of) the red supergiant star Antares, the heart of Scorpius. In both images, the star can be seen to the left (east) of the moon’s western limb. South is up and west is to the right.

July’s full moon is known as the Full Buck Moon as bucks begin to grow new antlers at this time or as the Thunder Moon as July is the month for thunderstorms in many northern hemisphere locations. This year’s Thunder Moon occurs on Tuesday, 19 July, 2016.

Credit to DW Rose for this article’s featured image of the June, 2009 Strawberry Full moon.

Imagination is more important than knowledge 585px-Albert_Einstein_signature_1934(invert)
An index of all articles in this blog can be found here.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s